Thermic telephone.



PIETER DE LANGE & ROBERTAE'RNO-UT BARON VAN LYNDEN.

IHERMIG TELEPHONE.

APPLlcAloN min Nov. 4, 1915.

LQQQH, Patented' 00h10, 1916 Juve/:fors

' I y Jomey unirsi); sraras raranr ernten P'IETER DE LANGE AND ROBERT AERNOUT BARON VAN LYNDEN, 'OF UTRECHT, NETHEE` LANDS, AASSIGENOBtS TO NAAMLOCZE VENNOOTSCHAP DE NEBERLANDSCHE THERMO- TELEPHOGN MAATSCHAPEIJ, OF UTRECHT, NETHERLANDS, A CORPORATION Ol? NETHERLANDS.

THERMIG TELEPHONE.

` Specification of Letters Patent. Ptented C. 10, lgln Application filed November 4, 1915.l Serial No. 59,626.

telephones a perfect reproduction of theI sound, and particularly of sibilant and labial sounds, can only be attained when the volume of the sounding chamber of the thermi'c telephone is accurately tuned to suit the heating conductors disposed in it. Ac-

cordingto our invention this result is obtained in a simple and yet very eilicientmanu ner by arranging in the sound chamber an insertion partly filling up the space therein. The tuning of the sounding chamber corresponds to the shape and dimensions of said insertion, and with* an insertion yof suitable form and size, the sounding chamber may be so tuned as to adapt itself to the action of the heating conductors. Preferably, the insertion is made exchangeable and of agood conductor of heat so as to enable it to rapidly discharge the heat from the sounding chamber, which has a favorable elfect on the reproduction of sound. The insertion body may be so formed and arranged in the sounding chamber that it covers the opening of the sounding chaxnber, thus protecting the heat wires. in sald' The inchamber from outside influences. sertion body may also be utilized for firmly connecting and supporting the parts constituting the thermic telephone.

Reference is to be had to the accompanying drawingslin which our invention is illustrated by way of example.

Figure l is an elevation, partly in section,

of a thermic telephone according to this invention,` F ig. 2 shows the insertion in eleva- 1 tion, and Fig. 3 in plan view.

tol

Referring to Fig. 1, the thermic telephone comprises a cylindrical support 2 of insulatins material for the heatingconductors 1" QThis "support is mounted in the lower portion of a hood 4 forming the sounding chamber 3 and having a sound opening 11 at the top, and rests against a shoulder 5 provided in the inner wall of said hood.

. The support "l is held in position by means of a plug 9 screwedinto the open end of hood 4. The branches of the arched heating conductors l are passed with -their ends through the support 2 and are bent so'as to form feet 6 which lie against the lower face of the support 2. These feetAv are engaged by the similarly bent ends 7 of eurent con- .ductors 8. fixed `in plug 9. These conductors have eyes at their free ends to which the conductor wires 8 may be connected. A bore 10 in plug 9 permits the 'passage of said conductor wires.

Between the support 2 for the heating conductors 1 and the top of hood 4 is .interchangeably arranged an insertion '12, Figs.

2 and 3, widened at the top so as to resemble a mushroom. lThe stem of the insertion is preferably rounded at its base 13 and rests in a correspondingly shaped central recess 1.4 of the support 2. The mushroom-shaped upper portion of the insertion body engages 'the inner arch of the hood 4, so that the sound opening 11 is covered by it so as to prevent any damage to the heating conduc tors. The necessary communication between the sound chamber 3 and the sound opening 11 is established through radial grooves 15' in the mushroom head which open into a central recess 16 opposite the sound opening 11 in the hood 4. On the parts 4, 2 andv 9 heilig assembled, the insertion body forms a connection between the support 2 and the hood which contributes to strengthening the construction of the telephone. By se. lecting an insertion of suitable size and shape, the volume of the soundchamber 3 may be accurately'tuned to conform lto the action of the heatingI conductors 1. As the insertion is made of a material which is a good conductor of heat, such as metal it assists the rapid discharge of heat from the sound chamber 3, which, as proved by experience, considerably improves the sound re' production.

It is obvious that our invention is not limited rto the precise form of the. insertion 12 illustrated in the drawings; modiiications krnay be made in various respects acci'irdingto circumstances without departing from the spirit of ourinvention.v i

We claim: i

1. In a I thermic telephone, a sounding chamber, having a sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insertion in said sounding chamber adapted to tune said sounding chamber in conformity with the action of the heating wires.

2. Inl a theriiiic telephone, a sounding chamber, having a sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an eX- changeabie insertion in said sounding chamber adapted to tune said sounding chamber in conformity with the action of the heating Wires'.

3. In a thernnc telephone, a sounding chamber, having a sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insei-tion inade of a good conductor of heat in said sounding chamber said insertion being adapted'to tune said sounding chamber in conformity with the action of the heating w res.

a. In a thermic telephone, a sounding chamber, having a sound opening, heating y conductors in said sounding chamber, a support for said heating conductors and an in sertionwidened at the top in said sounding chamber said insertion being adapted to tune saidV sounding chamber in conformity with the action of the heating wires.

5. In a thermic telephone, a sounding chamber, having a sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insertion in said sounding chamber adapted to time said sounding chamber in conformity with the action of the heating Wires, said insertion being arranged in front of the sound opening in said sounding chamber.

G. In a therinic telephone, a. sounding chamber, having a sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insertion widened at the top in said sounding chamber said insertion being adapted to time said sounding chamber in conformity with the action of the heating Wires, and grooves for the passage of the sound waves at the top of said widened part of said insert-ion.

7. In a thermic telephone, a sounding chamber, having a sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insertion widened at the top insaid sounding chamber said insertion being adapted t0 time said sounding chamber in conformity with the action of the heating Wires, and radial grooves for the passage of the sound waives at the top of said widened part of said insertion.

S. In a thermic telephone, a sounding chamber, haring a. sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insertion in said sounding chamber adapted to tune said sounding chamber in conformity with the action of the heating wires, said insertion being arranged between the top of said sounding chamber and said support for the heating conductors in the manner of a stay.

9. In a thermic telephone, a sounding chamber, having av sound opening, heating conductors in said sounding chamber, a support for said heating conductors and an insertion in said sounding chamber adapted to tune said sounding chamber in conformity with the action of the heating wires, said insertion being arranged between the top of saidsourfding chamber and said support for the heating conductors in the manner of a stay and means for exerting pressure on said support and Said insertion.

In testimony whereof, we have signed this specification.

PIETER DE LANGE. ROBERT AERNOUT BARON VAN LINDEN. 

